Tube sheet apparatus and heat exchanger

ABSTRACT

An apparatus (e.g., tube sheet) includes a plate piece, a sleeve piece, and a tube piece. The plate piece defines a hole. The sleeve piece has first and second ends; the second end is shaped to fit through the hole for attachment of the sleeve piece to the plate piece. The tube piece also has first and second ends. Inner and outer cross-sectional geometries of the tube piece and the sleeve piece (e.g., in the case of round tubes, inner and outer diameters) are shaped for the first end of the tube piece to fit in the first end of the sleeve piece and to form a continuous interior fluid flow path from the second end of the tube piece through the plate piece when the sleeve piece is disposed in the hole and attached to the plate piece and the tube piece is disposed in the sleeve piece.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/425,187 filed 22 Nov. 2016, which is incorporated herein by reference.

FIELD

Embodiments of the subject matter disclosed herein relate to systems and methods for the joining of tubes to plates or sheets in general. Other embodiments relate to heat exchangers.

BACKGROUND

Tubes are frequently joined to plates during the construction of shell-and-tube heat exchangers. In such exchangers, it is common for thermal stress to occur at the joint where a tube joins a plate often due to differences in material composition and mass. Tubes are commonly joined by pneumatic or hydraulic pressure, or by roller expansion.

In another method, sidewalls of holes drilled in plates to accommodate tubes have a series of grooves reamed into the walls; the tube wall is then mechanically or explosively expanded into the grooves for forming a mechanical joint and seal. This often creates a deformation in the interior-wall of the tube where undesired materials can accumulate and flow through the tube is disrupted. In instances where the tube and plate materials are weldable, the tube-plate joint can be strengthened by applying a seal weld or strength weld to the joint. A strength weld has a tube slightly recessed inside a tube hole or slightly extended beyond the plate; this weld adds material to the resulting lip. In a seal weld, no material is added. Instead, the tube and plate materials are fused together.

In the often-harsh environment of a heat exchange system, thermal gradients and materials with differing coefficients of thermal expansion often result in differential thermal expansion of tube and plate pieces. When temperature gradients are increased, stress at the site of the tube-to-plate joint is also increased. Increased stress often results in deformation or early failure of the joint.

BRIEF DESCRIPTION

In an embodiment, an apparatus (e.g., a tube-to-sheet joint, a tube sheet, or parts that can be assembled to form a tube-to-sheet joint or tube sheet) includes a plate piece, a sleeve piece, and a tube piece. The plate piece defines a hole, that is, a hole extends through the plate piece. The sleeve piece has first and second ends; the second end is shaped to fit through the hole for attachment of the sleeve piece to the plate piece. The tube piece also has first and second ends. Inner and outer cross-sectional geometries of the tube piece and the sleeve piece (e.g., in the case of round tubes, inner and outer diameters) are shaped for the first end of the tube piece to fit in the first end of the sleeve piece and to form a continuous interior fluid flow path from the second end of the tube piece through the plate piece when the sleeve piece is disposed in the hole and attached to the plate piece and the tube piece is disposed in the sleeve piece.

Thus, according to one aspect, the sleeve piece is attached to the plate piece, and the tube piece is attached to the sleeve piece, thereby forming a tube-to-sheet joint where the sleeve piece may act as a thermal and/or mechanical buffer between the tube piece and the plate piece. The sleeve piece and tube piece are shaped to establish the continuous interior fluid flow path, such that even though the tube piece is attached to the plate piece by way of the sleeve piece, a flow of fluid through the tube piece and sleeve piece is not impeded by the sleeve piece or the interface between it and tube piece.

In an embodiment, the tube piece, sleeve piece, and plate piece are part of a heat exchanger. The heat exchanger includes additional sleeve pieces and tube pieces, which are associated, as mated pairs, with additional holes in the plate piece.

In an embodiment, the tube sheet, sleeve piece, and/or plate piece are a monolithic structure made using an additive manufacturing process, with each of the pieces made from a different material (e.g., for thermal buffering).

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter described herein will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

FIG. 1 is a side elevation (longitudinal), cross-sectional view of an apparatus in an assembled form, according to an embodiment;

FIG. 2 is a top plan (transverse), cross-sectional view of another embodiment of the apparatus of FIG. 1, taken along line 2-2 in FIG. 1;

FIG. 3 is a top plan, cross-sectional view of the embodiment of the apparatus of FIG. 2, taken along line 3-3 in FIG. 1;

FIG. 4 is a side elevational, cross-sectional view of the apparatus of FIG. 1, shown in an exploded, pre-assembled state;

FIG. 5 is a side elevational, cross-sectional view of another embodiment of an apparatus, shown in an exploded, pre-assembled state;

FIG. 6 is a transverse cross-sectional view of an embodiment of a heat exchanger;

FIG. 7 is a side elevation, cross-sectional view of an apparatus in an assembled form, according to another embodiment;

FIG. 8 is a side elevation, cross-sectional view of an apparatus in an assembled form, according to another embodiment;

FIG. 9 is a side elevation, cross-sectional view of another embodiment of an apparatus;

FIG. 10 is a side elevation, cross-sectional view of another embodiment of an apparatus; and

FIG. 11 is a side elevation, cross-sectional view of another embodiment of an apparatus.

DETAILED DESCRIPTION

Embodiments described herein relate to systems and methods for joining a tube to a sheet. Other embodiments relate to shell-and-tube heat exchangers or other heat exchangers. According to one aspect, tubes are connected to a plate or sheet by intermediary sleeve pieces, for example, the sleeve pieces are disposed in holes formed in the plate or sheet, and the tubes are received in the sleeve pieces. The sleeve pieces thereby act as a mechanical and/or thermal buffer between the tubes and the plate or sheet. To avoid impeding the flow of fluid through the tubes, the tubes and sleeve pieces are configured/shaped, as described herein, for a continuous fluid flow path through the tubes and sleeve pieces. For example, the tubes and sleeve pieces may be configured to establish a constant diameter flow path in the interior transition region between the tubes and sleeves pieces, thereby avoiding any internal ridges, creases, steps, etc. that would impede fluid flow or trap contaminants.

According to one aspect, “thermal expansion coefficient” refers to, and/or is a measure of, how the size of an object changes with a change in temperature. Thus, an “intermediate thermal expansion coefficient” refers to a thermal expansion coefficient value anywhere between higher and lower thermal expansion coefficient values. According to one aspect, “continuous geometry” refers to the location of the joining or blending of one element to another wherein the joining or blending of the two elements results in a contiguous piece. For example, in the joining of two pieces containing an interior passageway between the two elements, there is no intrusion into or disruption of the interior passage that results from the joining of the elements, exclusive of a seam. According to one aspect, the term “tube” refers to any hollow geometry where a perimeter wall defines an interior passage space from an exterior environment. By way of non-limiting examples, tubes may include hollow cylinders (i.e., round tubes), hollow rectangles (i.e., square or rectangular tubes), and members where there are differing cross-sectional areas between one end and another end. According to one aspect, the term “cross-sectional geometry” refers to the shape of the part if it was cut at a given point, usually perpendicular to the long axis of the part. By way of non-limiting example, the cross-sectional geometry of a cylindrical tube (i.e., round tube) would comprise the inner and outer diameters of the tube in addition to the overall shape. In like fashion, a cross-sectional geometry for the end of a tube could have an inner circular diameter and an outer edge, of a different shape. For example, a round passage of inner diameter “d” could be embedded in a rectangular block with an outer length and width.

According to another aspect, the terms “sheet,” “plate” (or “plate piece”), and “tube sheet” are synonymous in referring to a base material to which one or more tubes are attached. Sheets and tube sheets may extend the interior passages of tubes when connected, may form a cap over a tube when attached, or may introduce elements into the interior passage of the tube when attached. Sheets and tube sheets may be made out of any material similar or dissimilar to tubes. According to another aspect, the terms “tube sleeve,” “sleeve,” and “sleeve piece” are refer to an intermediary element (e.g., tubular element) placed between tubes and sheets. Sleeves may have their own interior or exterior geometries independent of any individual sheets and tubes.

FIGS. 1 and 4 show cross-sectional views (assembled and exploded, respectively) of an embodiment of an apparatus 100, e.g., a tube-to-sheet joint, which may be part of a heat exchanger. A plate piece 102 (also referred to as a tube sheet) is interfaced with a sleeve 104 (also referred to as a sleeve piece) which is interfaced with a tube 106, also referred to as a tube piece. (The sleeve and tube in combination are occasionally referred to herein as a tube assembly, simply to recognize that there may be plural such assemblies, i.e., sleeve and tube mated pairs, associated with a single plate piece having plural holes, such as in a heat exchanger.) An interior joint 110 is formed by an abutment of the tube 106 against the interior of the sleeve 104 and does not protrude into the passageway formed across the interface. An exterior tube and sleeve joint 108 can be formed by brazing, welding, friction fitting, etc. The sleeve 104 interfaces with the plate piece 102 and may be secured, for example, by a sealing weld 112. A sleeve-plate joint or interface 114 may be formed through tight-tolerance fitting of the sleeve 104 within a hole 116 defined by the plate piece.

To explain further, in embodiments, the plate piece 102 defines a hole 116, e.g., the hole is formed in or otherwise extends through the plate piece. The sleeve piece 104 has first and second ends 118, 120; the second end 120 is shaped to fit through the hole for attachment of the sleeve piece to the plate piece. The tube piece 106 also has first and second ends 122, 124. Inner and outer cross-sectional geometries of the tube piece and the sleeve piece (e.g., in the case of round tubes, inner and outer diameters—see FIGS. 2 and 3), discussed in more detail below, are shaped for the first end 122 of the tube piece to fit in the first end 118 of the sleeve piece and to form a continuous interior fluid flow path 126 from the second end of the tube piece through the plate piece when the sleeve piece is disposed in the hole and attached to the plate piece and the tube piece is disposed in the sleeve piece.

In another aspect, when the first end 122 of the tube piece 106 is disposed in the first end 118 of the sleeve piece 104, an inner cross-sectional geometry 128 of the second end 120 of the sleeve piece 104 conforms to an inner cross-sectional geometry 130 of the first end 122 of the tube piece 106, forming a continuous geometry across the interior transition (joint 110) between the sleeve and the tube piece.

In another aspect, when assembled (such as shown in FIG. 1), the first end 122 of the tube piece 106 is disposed in and attached to the first end 118 of the sleeve piece 106, with an outer cross-sectional geometry 132 of the first end of the tube piece conforming to an inner cross-sectional geometry 134 of the first end 118 of the sleeve piece 106 and forming joint 108. The second end 120 of the sleeve piece 106 is disposed through the hole 116 of the plate piece 102 and attached to plate piece forming the joint 114. The inner cross-sectional geometry 128 of the second end 120 of the sleeve piece 106 conforms to the inner cross-sectional geometry 130 of the first end 122 of the tube piece 106, forming the continuous geometry across the joint 110.

As mentioned, the tube 106 (or, more specifically, the first end of the tube that fits in the sleeve) may be a round tube, a square tube, a shape other than square or round, or it may have a mix of shapes, i.e., different inner and outer cross-sectional geometries, such as a square outer cross-sectional geometry and a round inner cross-sectional geometry, from the perspective of a plane normal to the long axis of the tube. (The inner cross-section geometry of the first end of the sleeve piece, into which the tube fits, may be shaped to correspond to the outer cross-sectional geometry of the first end of the tube.) Thus, the embodiment of FIGS. 1 and 4 is broadly directed to any shape, whereas the apparatus 136 of FIGS. 2 and 3 is directed to the more specific embodiment of a round tube and round tubular sleeve having circular inner and outer cross-sectional geometries defined by inner and outer diameters of the tube and sleeve, as an example.

In an embodiment, the first and second ends of the sleeve piece have different inner cross-sectional geometries, respectively (134, 128), such that a transition between the first and second ends of the sleeve piece defines an interior shoulder 138. The outer cross-sectional geometry 132 of the first end of the tube piece matches the inner cross-sectional geometry 134 of the first end of the sleeve piece, and the inner cross-sectional geometry 130 of the first end of the tube piece corresponds to the inner cross-sectional geometry 128 of the second end of the sleeve piece, for the first end 122 of the tube piece to abut the shoulder 138 and to establish the continuous geometry at the interior junction of the tube and sleeve.

In another embodiment, with reference to FIG. 5, the sleeve piece 104 has a uniform inner cross-sectional geometry 140 (e.g., the same diameter from the first end through the second end). The outer cross-sectional geometry 132 of the first end of the tube piece corresponds to the uniform inner cross-sectional geometry of the sleeve piece. The first end of the tube piece is configured to extend entirely through the sleeve piece, for the continuous interior fluid flow path to be established by the interior of the tube piece. That is, the fluid flow path is defined solely by the interior of the tube piece, and the fluid (liquid or gas) does not come into contact with the interior of the sleeve.

In an embodiment, with reference to FIG. 6, a heat exchanger 142 includes a plate piece 102 with plural holes, and plural mated sleeve and tube pairs, each including a respective tube 106 and sleeve 104, disposed in the holes and attached to the plate piece. The tubes may extend between two sides of the heat exchanger, with each such tube being held in place attached between two plates/walls of the heat exchanger by two sleeves, one at either end of the tube. The plates/walls of the heat exchanger may be part of, and/or define, a housing of the heat exchanger. Additional ports may be provided for ingress and egress of a first fluid (from a first fluid source) into the interior (inner volume) of the housing around the exterior of the tubes, for heat exchange with a second fluid (from a second fluid source) passing through the tubes. (FIG. 6 does not show the additional lines, tubes, ducts, etc. that would be connected to, and/or part of, the heat exchanger, for routing fluids through fluid circuits that include the heat exchanger and fluid sources.) In terms of the tubes, sleeves, and sleeve-plate interface, the heat exchanger may be alternatively configured as per any of the other embodiments set forth herein. For example, the heat exchanger could be provided with sleeves as shown in FIG. 5, such that the tubes extend all the way through the plate/wall.

The tube, sleeve, and/or plate piece or sheet may be made of metal, either the same metal or different metals. Different grey shading in the figures represents individual parts in cross section, but does not mean the parts are necessarily made of different materials. Further, one or more of the parts may be made from non-metal materials, such as polymers, ceramics, or composites. In one embodiment, the tube, plate, and sleeve pieces are each made of different materials, with a thermal coefficient of the material of the sleeve piece selected to act as a thermal buffer between the tube and plate pieces.

In an embodiment, the first end of the tube piece, defined by the outer cross-sectional geometry of the first end of the tube piece, is at least one of brazed, welded, or mechanically coupled to the first end of the sleeve piece, defined by the inner cross-sectional geometry of the first end of the sleeve piece. Alternatively or additionally, the sleeve piece may be welded, mechanically coupled, and/or brazed to the plate piece.

In an embodiment, the sleeve piece is removably attached to the plate piece, for example, by way of a press fit (tight friction fit), de-couplable adhesive, removable weld, etc., so that sleeves and/or tubes can easily be removed and replaced for repair or cleaning.

FIG. 7 shows a cross-sectional diagram of an assembled joint according to an embodiment. The plate piece 102 is interfaced with the sleeve 104, which is interfaced with the tube 106. Sleeve-plate/sheet joint 144 is a mechanical interface, e.g., screw threads. Interior joint 110 is formed by an abutment of the tube 106 against the interior of the sleeve 104 and does not protrude into the passageway formed across the interface. Exterior tube and sleeve joint 108 can be formed by brazing, welding, friction fitting, etc.

FIG. 8 shows a cross-sectional diagram of an assembled joint according to an embodiment. The plate piece 102 is interfaced with a sleeve 146, which is interfaced with tube 106. Sleeve-plate/sheet joints 148, 150 may be singularly or dually secured by at least one of welding, mechanical fitting, friction fitting, and/or brazing. Interior joint 110 is formed by an abutment of the tube 106 against the interior of the sleeve 104 and does not protrude into the passageway formed across the interface. Exterior tube and sleeve joint 108 can be formed by brazing, welding, friction fitting, etc.

FIG. 9 shows a cross-sectional view of an assembled joint according to an embodiment. Plate piece 102 is fitted with an integrated tube-and-sleeve member 152 formed by additive manufacturing or other techniques. Interior joint 154 is marked as a transition point where the material of 152 a blends with the material of 152 b, forming integrated tube-and-sleeve member 152. Exterior joint 156 may be further shaped to more fully secure integrated piece 152 to plate 102. A plate and integrated piece joint 158 may be formed by any technique.

FIG. 10 shows a cross-sectional view of an assembled joint according to an embodiment. Plate piece 160, comprised of materials 160 a comprising the base stock of the tube sheet and 160 b comprising the tube-to-plate/sheet interface material, is interfaced with tube 106. Materials 160 a and 160 b are interfaced at joint 162 defined as a transitional gradient zone of materials formed by additive manufacturing techniques and the like. Interior joint 110 is formed by abutment of tube 106 against material 160 b. Exterior joint 108 can be formed by brazing, welding, friction fitting, etc.

FIG. 11 shows a cross-sectional view of a unified interface structure 164 according to an embodiment. The integrated tube-and-sleeve zone 166 includes an interior joint 168 with continuous geometry and no seam, as marked as a transition point where the material of 166 a blends with the material of 166 b, and is further interfaced at joint 170 represented as the zone where material 166 b blends with sheet stock material 166 a.

In any of the embodiments herein, the plate piece and the tube assemblies may be a monolithic structure formed using an additive manufacturing process, with the plate piece, sleeve pieces, and/or tube pieces being composed of different materials and defined by boundaries between the different materials. Reference is made to U.S. application Ser. No. 15/821,729, filed 22 Nov. 2017 and incorporated herein by reference in its entirety, for further detail regarding additive manufacturing processes and monolithic structures. Further, in any of the embodiments herein, the sleeve and plate pieces may be constructed as a single unit with a material gradient marking the boundary of the sleeve and plate pieces, e.g., using additive manufacturing processes.

In an embodiment, the sleeve piece includes two or more lateral halves or other lateral sections, which are configured to be mated together around the tube piece and fastened together using fasteners, welding or brazing, adhesives, or otherwise, to form the sleeve piece as illustrated in the drawings.

In an embodiment, an apparatus includes a tube piece made of a first material with inner and outer cross-sections and a first end with first outer and inner geometries. The apparatus also includes a plate piece made of a second material of a first thickness and having a hole with at least first and second cross-sections. The apparatus also includes a sleeve piece with first and second ends with first and second inner and outer cross-sectional geometries, made of a third material with a thermal coefficient intermediate of thermal coefficients of the first and second materials of the tube and sheet pieces. The first end of the tube piece is attached and fitted into the first end of the sleeve piece, with the first outer cross-section geometry of the tube piece complementary to the first inner cross-section geometry of the sleeve piece, forming a first joint. The first joint is sealed by at least one of a weld or braze. The second end of the sleeve piece is disposed through the hole of the plate piece and attached to the plate piece forming a second joint. The sleeve piece, at the second joint, is at least one of removably attached to the plate piece, welded, brazed, and/or mechanically coupled into place with the plate piece. The second inner cross-sectional geometry of the first end of the sleeve piece conforms with the first inner geometry of first end of the tube piece forming a continuous geometry across the length of the first joint free of distortions in the inner geometries of both the sleeve piece and the tube piece caused by the action of joining the pieces together.

In another embodiment, a mechanical coupling of the sleeve piece at the second joint is at least one of: threading, mechanical expansion, or bolting to the plate piece.

In another embodiment, at least one of brazing and welding at the first joint utilizes fill material with a compatible thermal expansion coefficient.

In another embodiment, the first joint is sealed using mechanical means.

In another embodiment, the second cross-section of the hole in the plate piece forms a positive stop for seating the second end of the sleeve piece.

In another embodiment, the inner and outer cross-sectional geometries of the tube and sleeve pieces are tailored to minimize anticipated stress levels at the first and second joints.

In another embodiment, the tube, plate, and sleeve pieces are components of a tube-and-sheet heat exchanger.

Another embodiment relates to an apparatus that includes a sleeve comprising a sleeve body with a first end and a second end. The sleeve body defines a througbore extending along a center axis of the sleeve body from a first opening in the first end to a second opening in the second end. The sleeve further includes an interior perimeter step attached to the first end of the sleeve body, the step defining the first opening. A major inner cross dimension of the first opening is smaller than a major inner cross dimension of the throughbore, such that the sleeve body and the step form a shoulder in an interior of the sleeve. The major inner cross dimension of the throughbore corresponds to an outer dimension of a tube to be received in and attached to the sleeve such that when the tube is received in the sleeve the tube engages an inner wall of the sleeve body and the shoulder. An outer dimension of the sleeve corresponds to an opening that extends through a sheet to which the sleeve and tube are to be attached, such that when the sleeve is received in the opening in the sheet the sleeve engages an inner sidewall of the opening in the sheet. A length of the sleeve along the center axis is longer than a thickness of the sheet such that when the sleeve is received in the opening with the first end of the sleeve body lying flush to a flat surface of the sheet the second end of the sleeve lies spaced apart from an opposite, second surface of the sheet.

In another embodiment, the materials comprising sleeve, tube, and sheet have differing thermal coefficients.

In another embodiment, the tube, sheet and sleeve pieces are joined by at least one of welding, brazing, or mechanical coupling.

In another embodiment, the geometry of the throughbore is consistent across all piece joints and does not follow outer geometry.

In another embodiment, the tube, sheet, and sleeve pieces are part of a tube-sheet heat exchanger.

Another embodiment relates to an apparatus that includes a tube piece, a sleeve piece, and a plate piece. The tube piece and the sleeve piece are manufactured as a unitary body with a material gradient demarcating the boundary between the tube piece and the sleeve piece. The unitary body is joined to the plate piece.

Another embodiment relates to an apparatus that includes a tube piece, a sleeve piece, and a plate piece. The sleeve piece and the tube piece are manufactured as a unitary body with a material gradient demarcating the boundary between the plate piece and the sleeve piece. The tube piece is joined to the unified plate-sleeve piece.

Another embodiment relates to an apparatus that includes a tube piece, a sleeve piece, and a plate piece. The pieces are manufactured as a unitary body with a material gradient demarcating the boundaries between the pieces.

In another embodiment, a method includes inserting a first end of a tube piece, having the first end and at least a second end, a throughbore, and at least first inner and outer cross-sections, into a first end of a sleeve piece having a first end and a second end, a throughbore, a first inner cross-section at the first end and a first outer cross-section at the first end, and a second inner cross-section and a second outer cross-section at the second end; and inserting the second end of the sleeve piece into a hole in a plate piece with at least a first thickness. The first inner cross-section of the first end of the sleeve piece corresponds to the first outer cross-section of the first end of the tube piece. The second inner cross section of the second end of the sleeve piece is the same as the inner cross-section of the first end of the tube piece, forming a continuous cross-section across the joint of the tube piece and the sleeve piece.

In another embodiment of the method, the hole in the plate piece is defined by at least two different cross-sectional geometries.

In another embodiment of the method, at least one of the at least two cross-sectional geometries is shaped to accommodate attachment of the sleeve piece to the plate piece.

In another embodiment of the method, the tube piece, sleeve piece, and plate piece are each made of different materials.

In another embodiment of the method, the sleeve piece is made of a material whose coefficient of thermal expansion is an intermediate between thermal coefficients of the materials forming the tube piece and plate piece.

In another embodiment of the method, the first end of the tube piece is inserted into the first end of the sleeve piece and the change in cross-section from the first to second inner cross-sections of the sleeve piece creates a positive stop for abutment of the first end of the tube piece against the sleeve piece.

In another embodiment of the method, the tube piece is joined to the sleeve piece by at least one of brazing, welding, and mechanical coupling.

In another embodiment of the method, the sleeve piece is welded to the plate piece.

In another embodiment of the method, the sleeve piece is removably attached to the plate piece.

In another embodiment of the method, the first outer cross-section of the first end of the sleeve piece is different from the second outer cross-section of the second end of the sleeve piece.

In another embodiment of the method, the first outer cross-section of the first end of the sleeve piece is configured to minimize thermal stress between the sleeve piece and tube piece while maximizing attachment surface area between the two pieces.

In another embodiment of the method, the second outer cross-section of the second end of the sleeve piece is configured to minimize thermal stress between the sleeve piece and plate piece while maximizing attachment surface area between the two pieces.

The foregoing description of certain embodiments of the inventive subject matter will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (for example, processors or memories) may be implemented in a single piece of hardware (for example, a general purpose signal processor, microcontroller, random access memory, hard disk, and the like). Similarly, the programs may be stand-alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. The various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

The above description is illustrative and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the inventive subject matter, they are by no means limiting and are exemplary embodiments. Other embodiments may be apparent to one of ordinary skill in the art upon reviewing the above description. The scope of the inventive subject matter should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure. And, as used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the inventive subject matter are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.

This written description uses examples to disclose several embodiments of the inventive subject matter and also to enable a person of ordinary skill in the art to practice the embodiments of the inventive subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the inventive subject matter is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. An apparatus comprising: a plate piece defining a hole; and a tube assembly comprising: a sleeve piece having first and second ends, wherein the second end of the sleeve piece is shaped to fit through the hole for attachment of the sleeve piece to the plate piece; and a tube piece having a first end and a second end, wherein inner and outer cross-sectional geometries of the tube piece and the sleeve piece are shaped for the first end of the tube piece to fit in at least the first end of the sleeve piece and to form a continuous interior fluid flow path from the second end of the tube piece through the plate piece when the sleeve piece is disposed in the hole and attached to the plate piece and the tube piece is disposed in the sleeve piece.
 2. The apparatus of claim 1, wherein: the first and second ends of the sleeve piece have different first and second inner cross-sectional geometries, respectively, such that a transition between the first and second ends of the sleeve piece defines an interior shoulder; and an outer cross-sectional geometry of the first end of the tube piece matches the inner cross-sectional geometry of the first end of the sleeve piece, and an inner cross-sectional geometry of the first end of the tube piece corresponds to the inner cross-sectional geometry of the second end of the sleeve piece, for the first end of the tube piece to abut the shoulder and to establish a continuous geometry from the tube piece to the sleeve piece for the continuous interior fluid flow path.
 3. The apparatus of claim 1, wherein: the sleeve piece has a uniform inner cross-sectional geometry; and the first end of the tube piece has an outer cross-sectional geometry that corresponds to the uniform inner cross-sectional geometry of the sleeve piece, wherein the first end of the tube piece is configured to extend entirely through the sleeve piece, for the continuous interior fluid flow path to be established by the interior of the tube piece.
 4. The apparatus of claim 1, wherein the sleeve piece and the tube piece are round tubes and the inner and outer cross-sectional geometries of the tube piece and the sleeve piece are inner and outer diameters of the tube piece and the sleeve piece, respectively.
 5. A heat exchanger comprising the apparatus of claim 1, wherein the sleeve piece is attached to the plate piece, the first end of the tube piece is fit into the first end of the sleeve piece, and the tube piece is attached to the sleeve piece, and wherein the plate piece defines the hole and plural additional holes, and further comprising plural additional tube assemblies respectively associated with the plural additional holes and attached to the plate.
 6. The heat exchanger of claim 5, wherein the plate piece and the tube assemblies are a monolithic structure formed using an additive manufacturing process, with the plate piece, sleeve pieces, and tube pieces being composed of different materials and defined by boundaries between the different materials.
 7. An apparatus comprising: a plate piece defining a hole; and a tube assembly comprising: a sleeve piece having first and second ends, wherein the second end of the sleeve piece is shaped to fit through the hole for attachment of the sleeve piece to the plate piece; and a tube piece having a first end shaped to fit in the first end of the sleeve piece, wherein when the first end of the tube piece is disposed in the first end of the sleeve piece, an inner cross-sectional geometry of the second end of the sleeve piece conforms to an inner cross-sectional geometry of the first end of the tube piece, forming a continuous geometry across an interior transition between the sleeve and the tube piece.
 8. The apparatus of claim 7, wherein: the inner cross-sectional geometry of the second end of the sleeve piece is different from an inner cross-section geometry of the first end of the sleeve piece, respectively, such that a transition between the first and second ends of the sleeve piece defines an interior shoulder; an outer cross-sectional geometry of the first end of the tube piece matches the inner cross-sectional geometry of the first end of the sleeve piece, and the inner cross-sectional geometry of the first end of the tube piece corresponds to the inner cross-sectional geometry of the second end of the sleeve piece, for the first end of the tube piece to abut the shoulder and to establish the continuous geometry across the interior transition between the sleeve and the tube piece.
 9. The apparatus of claim 7, wherein the sleeve piece and the tube piece are round tubes, the inner cross-sectional geometry of the second end of the sleeve piece is an inner diameter of the second end of the sleeve piece, and the inner cross-sectional geometry of the first end of the tube piece is an inner diameter of the first end of the tube piece that is equal to the inner diameter of the second end of the sleeve piece.
 10. A heat exchanger comprising the apparatus of claim 7, wherein the sleeve piece is attached to the plate piece, the first end of the tube piece is fit into the first end of the sleeve piece, and the tube piece is attached to the sleeve piece, and wherein the plate piece defines the hole and plural additional holes, and further comprising plural additional tube assemblies respectively associated with the plural additional holes.
 11. The heat exchanger of claim 10, wherein the plate piece and the tube assemblies are a monolithic structure formed using an additive manufacturing process, with the plate piece, sleeve pieces, and tube pieces being composed of different materials and defined by boundaries between the different materials.
 12. An apparatus comprising: a tube piece having a first end; a plate piece defining a hole; and a sleeve piece having first and second ends; wherein the first end of the tube piece is disposed in and attached to the first end of the sleeve piece with an outer cross-sectional geometry of the first end of the tube piece conforming to an inner cross-sectional geometry of the first end of the sleeve piece and forming a first joint; wherein the second end of the sleeve piece is disposed through the hole of the plate piece and attached to plate piece forming a second joint; and wherein an inner cross-sectional geometry of the second end of the sleeve piece conforms to an inner cross-sectional geometry of the first end of the tube piece, forming a continuous geometry across a third, interior joint between the first end of the tube piece and the second end of the sleeve piece.
 13. The apparatus of claim 12, wherein: the first end of the tube piece, defined by the outer cross-sectional geometry of the first end of the tube piece, is at least one of brazed, welded, or mechanically coupled to the first end of the sleeve piece, defined by the inner cross-sectional geometry of the first end of the sleeve piece; and the sleeve piece is at least one of welded, mechanically coupled, or brazed to the plate piece.
 14. The apparatus of claim 12, wherein the sleeve piece is removably attached to the plate piece.
 15. The apparatus of claim 12, wherein the sleeve and plate pieces are constructed as a single unit with a material gradient marking the boundary of the sleeve and plate pieces.
 16. The apparatus of claim 12, wherein the tube, plate and sleeve pieces are each made of different materials, a thermal coefficient of the material composing the sleeve piece selected to act as a thermal buffer between the tube and plate pieces.
 17. The apparatus of claim 12, wherein: the inner cross-sectional geometry of the first end of the sleeve piece defines a first interior opening of the sleeve piece that is wider than a second interior opening of the sleeve piece defined by the inner cross-sectional geometry of the second end of the sleeve piece, such that a transition between the first and second ends of the sleeve piece defines an interior shoulder; the first end of the tube piece is sized to abut the interior shoulder, with the inner cross-sectional geometry of the first end of the tube piece defining an interior opening of the tube piece that matches the second interior opening of the sleeve piece, to establish the continuous geometry across the third joint.
 18. The apparatus of claim 17, wherein: the sleeve piece and the tube piece are round tubes, with the inner cross-sectional geometry of the first end of the sleeve piece defining a first inner diameter of the sleeve piece that is wider than a second inner diameter of the sleeve piece defined by the inner cross-sectional geometry of the second end of the sleeve piece, such that a transition between the first and second ends of the sleeve piece defines an annular interior shoulder; the first end of the tube piece is sized to abut the annular interior shoulder, with the inner cross-sectional geometry of the first end of the tube piece defining an inner diameter of the tube piece that matches the second inner diameter of the sleeve piece, to establish the continuous geometry across the third joint.
 19. A heat exchanger comprising the apparatus of claim 12, wherein the tube piece is fluidly coupled to a first fluid source and a volume outside the tube piece is fluidly coupled to a second fluid source, for the tube piece to transfer heat between the first fluid and the second fluid.
 20. The heat exchanger of claim 19, wherein the plate piece, tube piece, and sleeve piece are a monolithic structure formed using an additive manufacturing process, with the plate piece, sleeve piece, and tube piece being composed of different materials and defined by boundaries between the different materials. 